Do those 2.4GHz radio controllers need frequency crystals? If yes what frq do they use? AM/FM? Is it true the users do not need to worry even if someone uses same frq as them? Pls enlighten me!

2.4ghz is the frequency

They do not use crystals

Each 2.4g radio scans the frequency band when it is turned on and picks a free channel, you will not get channel conflicts

Cheers

Fairly detailed read - aircraft slant, and a little out of date, but you'll get the basics -

http://www.rcmodelreviews.com/spreadspectrum01.shtml

good website! but seems like the 2.4Ghz Radio kits are very battery draining! i will keep them in view for now. thanks for the advices! cheers

they are not 2 draining at all.

well worth the money if you use your car where other cars are being used. alos a better settings system with them. they are worth there wieght in gold

Not sure where that came from.. all the 2.4Ghz transmitters I have only use 4 batteries (compared to 8 in every other tx). So less weight, and less cost in batteries.

My DX3S and DX3R use 4 AA batteries. I have 2500Mah rechargables in them and I dont have to charge but onces every 2-3 race days...

And I you dont need crystal... 2.4 will replace 27 & 75 in the next few years

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Oh.. but i saw some 2.4Ghz receiver requires additional batteries which will add on weight to the chassis... Although I know some dun need that and even the transmitter requires only 4 batteries... which is a plus factor! But the number of batteries determine the voltage not the amount of time it can last right? If i am not wrong... 4 batteries connected in series and 8 batteries in series will drain equally fast if the transmitter use alot of mah..

The receiver only needs its own batteries if it is being used in a nitro/petrol or the ESC does not have a built in BEC.

Power drain varies from radio to radio, some can chew them down quite quick while some will last for ages.

Some of the more modern radios are getting more power efficient, requiring less cells/voltage and usually lasting longer per charge also.

As you said though, 4 cells or 8 cells will drain at the same rate given a constant power draw, the difference is just the lower/higher voltage.

ok. i decie to get a 2.4Ghz. Anyone got a spektrum dx 2.0 or futaba 2pl-2.4Ghz for sale?